Improvement in spiral springs for railroad cars



J. MURRAY.

Improvement in Spiral-Springs for Railroad Cars.

No. 2,213. Patented Oct.15,1872.

UNITED STATES PATENT OFFICE.

JOHN MURRAY, OF NEW YORK, N. Y.

IMPROVEMENT IN SPIRAL SPRINGS FOR RAILROAD CARS.

Specification forming part of Letters Patent No! 132,213, dated October15, 1872.

To all Vwhom it may concern:

Be it known that I, JOHN MURRAY, of the city, county, and State of NewYork, have invented a new' and useful Improvement in Spiral Springs forRailway Gars and other purposes, of which the following is aspecification, reference being had to the accompanying drawing, whichrepresents an elevation of a spring embodying my invention.

It is necessary that a spiral'spring, which is designed to sustainpressure at opposite endsapplied as, for example, the bearing or buffersprings of railway carsshould have such pressure `applied to the surfaceof the entire terminal coils in order to secure the most favorableaction of the spring. This result is secured sometimes by providingspirallygroovecl seats for the endsof the spring; but this is attendedwith certain inconveniences and objections, and the more recent plan hasbeen to grind away or taper the ends of the spring so as to give themsurfaces at right angles to the axis of the spring. When the spring isformed of a flat or square rod, and having an angular sectional area,the proper taper may be given to one side or edge ofthe rod before theoperation of coiling, as the angular shape of the rod will. enable it tobe so held while being coiled, as to present the tapered side or edgesquarely at the end of the spring when coiled; but when the spring ismade of a round rod, or one having a circular sectional area, which onmany accounts is the preferable shape, the flattening or tapering of theends, so as to give the spring the desired surface at right angles tothe axis ofthe spring, can be done only after the spring is coiled, asthe natural tendency of a rod to twist in the act of coiling would makeit altogether uncerof metal, or one having a circular sectional area,the ends of which are conically tapered before ceiling, so that whilethe `rod is left free to twist, as it has a tendency to do in the act ofcoiling, the terminal coils of the spring will always present abearingsurface at right angles to the axis of the spring, and of courseobviating the necessity of filing or grinding the ends after coiling,for the purpose of getting such a surface-an operation that is eX-pensive .and troublesome.

The spring is formed of a round rod, A, of steel or other suitablemetal, that is coiled into a spiral in the ordinary manner, and by meansin common use. Before being coiled the ends c c are conically tapered.This may be done by rolling with rolls suitably constructed, bygrinding, or in any manner, at the option of the manufacturer. The tapershould extend far enough back upon the rod to give a i'lat bearing uponthe whole, or nearly the whole, of the terminal coils.

What I claim as my invention, and desire to secure by Letters Patent,is-

A spiral spring formed of a round rod or bar of metal,withconically-tapered ends, substantially as and for the purposesspecified'.

In testimony whereof l have hereto subscribed my n'ame to thisspecification this 19th day of July, 1870, before two subscribingwitnesses.

witnesses: JOHN MURRAY.

CUERAN DINsMoEE, R. R. Woon.

